section 1- the nature and variety of organisms Flashcards
characteristics of living organisms
movement, respiration, sensitivity, growth, reproduction, excretion, nutrition, respond
two types of cells
prokaryotic
eukaryotic
eukaryotic
plants animal fungi protoctists
prokaryotic
bacteria
what is an organelle
tiny structures within cells
plant cells
- plants are multicellular organisms
- cells contains chloroplasts and are able to carry out photosynthesis, it contains chlorophyll which is used in photosynthesis
- they have cellulose cell walls that surrounds the cell membrane, it supports and strengthens the cell
- the cell stores carbohydrates such as sucrose and starch
animal cells
- multicellular organisms
- do not contain chloroplasts and aren’t able to carry out photosynthesis
- no cell wall, usually have nervous co ordination and are able to move from one place to another
- often store carbohydrates as glycogen
- contains nucleus, contains genetic info that controls cell activity
- has cell membrane, controls what goes in and out of cell
- cytoplasm, gel like substance where most of cells chemical reactions happen
- ribosomes which are small organelles where proteins r made in cell
- contains mitochondria where most of the reactions for aerobic respiration takes place
- respiration transfers energy that the cell needs to work.
what do animal cells CONTAIN
cell membrane
nucleus
ribosomes
mitochondria
cytoplasm
what does a plant cell contain
vacuole
nucleus
cell wall
cytoplasm
ribosomes
chloroplasts
mitochondria
cell membrane
fungi
- some fungi are single-celled
- others have a body called mycelium, which is made up of hyphae ( threadlike structures)
- they can’t photosynthesise
- their cell walls are made of chitin
- most feed by saprotrophic nutrition
- they secrete extracellular enzymes into the area outside their body to dissolve their food, so they can then absorb the nutrients
- they can store carbohydrates as glycogen
protocists
- single celled and microscopic
- some have chloroplasts and are similar to plant cells
- others are more like animal cells
bacteria
- there are also single celled and microscopic
- dont have a nucleus
have a circular chromosome of DNA - some can photosynthesis
- most bacteria feed off other organisms - both living and dead
viruses
- these are particles, rather than cells and are smaller than bacteria
- they can only reproduce inside living cells. A virus is an example of a parasite - it depends on another organism to grow and reproduce
- they infect all types of organisms
- they come in loads of different shapes and sizes
- they dont have a cellular structure - they have a protein coat around some genetic material (either DNA or RNA)
levels of organisation
SIMILAR CELLS –> TISSUES –> organs –> organ system
state –> cells are specialised to carry out a particular function
what is a tissue
- tissue is a group of similar cells that work to carry out a specific function
- a tissue can contain more than one cell type
whats an organ
- an organ is a group of different tissues that work together to perform a function
what are organ systems made of?
organs work together to form an organ system, each system does a different job
What Are Stem Cells?
-Stem cells are unspecialized cells that have the ability to:
- Divide and produce more stem cells (self-renewal).
- Differentiate into specialized cells (e.g., nerve cells, muscle cells, or blood cells).
types of stem cells
- embryonic
- adult stem cells
whats cell differentiation
the process by which a cell changes to become specialised for its job
what do undifferentiated cells do
they divide to produce lots more undifferentiated cells
where are stem cells found
in early human embryos
where are adult stem cells found
bone marrow
can adult stem cells turn into any cell type
no
what cell types can adult stem cells turn into to
only certain ones like blood cells
where can stem cells from embryos and bone marrow be grown and why
they can be grown in a lab to produce clones (genetically identical cells) and made to differentiate into specialised cells to use in medicine or research
what does medicine use to cure disease
adult stem cells
whats an example of adult stem cells being used to cure disease
stem cells transferred from the bone marrow of a healthy person can replace faulty blood cells in the patient who receives them
what stem cells can also be used to replace faulty cells in sick people
embryonic stem cells
whats an example of embryonic stem cells being used to replace faulty cells in sick people
you could make insulin-producing cells for people with diabetes, or nerve cells for people paralysed by spinal injuries
whats a risk involved in using stem cells in medicine
stem cells being grown in the lab may become contaminated with a virus which could be passed on to the patient and so make them sicker
why would some people be against stem cell research
- they feel as though human embryos shouldnt be used for experiments bcs each one has the potential of becoming a human life
